Image displaying apparatus, and a method for adjusting vibrating condition of a reflection mirror in the image displaying apparatus

ABSTRACT

For enabling to prevent ill effects from being generated in the structures of a reflection mirror, even if increasing an output energy from a light source, thereby preventing ill influences from being exerted on the driving condition thereof, a mirror drive controller unit  7  reads out history data of the past, relating to temperature changes on a micro mirror  1,  from a first LUT holder unit  19.  Upon basis of the read-out history data of the past is presumed the temperature on the micro mirror  1  at the present time. The presumed temperature on the micro mirror  1  is temperature P temp of the micro mirror  1  at the present time, and upon that P temp are changed vibration (or oscillation) condition of the micro mirror  1  in the horizontal (H) direction and vibration (or oscillation) condition thereof in the vertical (V) direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image displaying apparatus,comprising therein a reflection mirror for displaying an object to beprojected by receiving and reflecting a light irradiated from a lightsource into a predetermined direction, and a method for adjustingvibrating condition of the reflection mirror in the image displayingapparatus.

2. Related Art

In recent years are tried applications of technologies, such as, MEMS(Micro Electro Mechanical System) and a semiconductor laser technology,into household electric appliances. As an example of that can be listedup an application into an image displaying apparatus, for drawing animage thereon, with using a laser light made of wavelength components ofvisible lights, as a light source thereof (for example, see thefollowing Non-Patent Document 1). Also, within an image displayingapparatus, comprising therein MEMS resonance mirrors is made a proposalof generating an image through raster scanning of a laser light, bymeans of that MEMS resonance mirrors, for a purpose of equalizing thebrightness of the image projected on a screen. In that proposal, whenconducting a laser scanning while outputting each pixel image data ofthree (3) primary colors, R, G and B, an adjustment is made on theintensity or strength of emission of the laser light depending uponspeed change of the raster scanning in the horizontal direction, therebyobtaining an even or uniform brightness on the screen at each of brightspots (for example, see the following Non-Patent Document 1).

[Patent Document 1] Japanese Patent laying-Open No. 2006-343397 (2006);and

[Non-Patent Document 1] Trends in Laser Light Sources for ProjectionDisplay (IDW '06 1939-1942 (page 1939, FIG. 2).

SUMMARY OF THE INVENTION

By the way, with the image displaying apparatus comprising therein theMEMS resonance mirrors, being pivotally supported so as to swing,freely, into the vertical direction and the horizontal direction, it ispossible to achieve an increase of color reproduction region and/or ahigh brightness, with a relatively low cost and with ease, inparticular, upon the image formed on the screen, by projecting the laserbeam lights emitted from the light source and reflected upon the MEMSresonance mirrors. This is due to the fact that, accompanying anadvancement of the semiconductor laser technology in recent years, it ispossible to achieve an increase of output energy from the laser lightsource and/or an increase of an efficiency in electric/photo conversion,and that it is also possible to achieve an increase in selectivity ofoscillation wavelengths within the visible lights.

However, in general, the reflectivity of the laser beam lights upon thereflection mirror (i.e., the MEMS resonance mirrors) is 90% or more orless than that, approximately, within a range of the visible lightwavelengths, and components of the remaining 10% of the laser beamlights, which are not reflected upon, are absorbed in the MEMS resonancemirrors, and almost of them are converted into heats on the MEMSresonance mirrors. For this reason, if increasing the output energy fromthe laser light source, in order to achieve the high brightness of animage or picture projected on the screen, then an amount of heats on theMEMS resonance mirrors is increased, thereby rising up temperature ofthe MEMS resonance mirrors; i.e., due to this, there is a possibility ofgenerating various ill effects on the structures of the MEMS resonancemirrors. In addition to that mentioned above, there is also apossibility of bringing about an ill influence upon swinging conditionof the MEMS resonance mirrors, which are pivotally supported so as toswing, freely, into the vertical direction and the horizontal direction.Therefore, with the conventional image displaying apparatus, actually,it is impossible to achieve the high brightness of the projection imageformed on the screen, by increasing the output energy from the laserlight source.

Accordingly, an object of the present invention is to provide an imagedisplaying apparatus, comprising there in reflection mirrors, which canvibrate in one (1) axial direction or two (2) axial directions, whereinthe structures of reflection mirrors thereof can be protected from beingaffected with ill influences applied thereupon, even if increasing theoutput energy from the light source for achieving the high brightness ofthe projection image.

An image displaying apparatus, provided according to a first aspect ofthe present invention, comprises: a reflection mirror, which isconfigured to display an image on a projection object, upon receiving alight irradiated from a light source thereon, to reflect it into apredetermined direction; a reflection mirror vibrating mechanism, whichis configured to vibrate said reflection mirror into a predetermineddirection; a temperature presuming unit, which is configured to presumetemperature on said reflection mirror, depending on driving condition ofsaid light source; and a vibration condition adjusting unit, which isconfigured to adjust condition of the vibration of said reflectionmirror by said reflection mirror vibrating mechanism, to becorresponding to the temperature on said reflection mirror, which ispresumed within said temperature presuming unit.

According to a preferable embodiment of the present invention, accordingto the first aspect thereof, said reflection mirror vibrating mechanismcomprises: a first vibration mechanism, which is configured to vibratesaid reflection mirror in a first axial direction; and a secondvibration mechanism, which is configured to vibrate said reflectionmirror in a second axial direction, perpendicular to said first axialdirection.

According to other embodiment differing from the above, said temperaturepresuming unit presumes the temperature on said reflection mirror, uponbasis of accumulated value data of a light amount irradiated from saidlight source, per every predetermined time-period.

Also, according to other embodiment differing from the above, saidvibration condition adjusting unit adjusts vibration amplitude,vibration frequency, or vibration phase of said reflection mirror bysaid reflection mirror vibrating mechanism, to be corresponding to thetemperature on said reflection mirror, which is presumed within saidtemperature presuming unit, appropriately.

Further, according to other embodiment differing from the above, theadjustment upon the vibration condition of said reflection mirror, whichis conducted by said vibration condition adjusting unit, is conductedsuch that a locus of the light reflected through said reflection mirroron said projection object is in conformity with an ideal condition ofthe locus of said light on said projection object.

An image displaying apparatus, provided according to a second aspect ofthe present invention, comprises: a reflection mirror, which isconfigured to display an image on a projection object, upon receiving alight irradiated from a light source thereon, to reflect it into apredetermined direction; a reflection mirror vibrating mechanism, whichis configured to vibrate said reflection mirror into a predetermineddirection; a photo detector unit, which is configured to output apredetermined electric signal, after detecting a light incident uponsaid projection object through said reflection mirror; a vibrationcondition detector unit, which is configured to detect a vibrationcondition of said reflection mirror, upon basis of the electric signaloutputted from said photo detector unit; and a controller unit, which isconfigured to control said reflection mirror vibrating mechanism, so asto bring the vibration condition of said reflection mirror into adesired vibration condition, upon basis of the vibration condition ofsaid reflection mirror, which is detected by said vibration conditiondetector unit.

According to a preferable embodiment of the second aspect of the presentinvention, said vibration condition detector unit detects vibrationamplitude, vibration frequency, or vibration phase of said reflectionmirror, which are obtained by measuring a distance between the electricsignals outputted from said photo detector unit.

Also, according to other embodiment differing from the above, said photodetector unit comprises: a photo transmitting member, which is disposedin said projection object and is configured to transmit a light incidentthereupon; and a photo/electric converter element, which is configuredto input the light transmitted through said photo transmitting member,so as to output a predetermined electric signal therefrom.

Also, according to other embodiment differing from the above, said photodetector units are disposed within said projection object, in pluralnumber of sets thereof.

Further, according to other embodiment differing from the above, saidlight source includes therein: a red color light source for irradiatinga red color light towards said reflection mirror; a green color lightsource for irradiating a green color light towards said reflectionmirror; and a blue color light source for irradiating a blue color lighttowards said reflection mirror.

Further, according to a method for adjusting vibration condition of areflection mirror, within an image displaying apparatus, having: areflection mirror, which is configured to display an image on aprojection object, upon receiving a light irradiated from a light sourcethereon, to reflect it into a predetermined direction; and a reflectionmirror vibrating mechanism, which is configured to vibrate saidreflection mirror into a predetermined direction, comprises thefollowing steps of: a first step for presuming temperature on saidreflection mirror, responding on driving condition of said light source;and a second step for adjusting vibration condition of said reflectionmirror by said reflection vibration mechanism, so as to fit thetemperature on said reflection mirror, which is presumed in said firststep.

According to the present invention, within the image displayingapparatus comprising the reflection mirror vibrating in a first axialdirection and a second axial direction, even when increasing an outputenergy from the light source, so as to obtain high brightness of theprojection image, it is possible to prevent ill effects from beinggenerated in the structures of the reflection mirror due to that, andtherefore it is possible to prevent ill influences from being extortedupon the driving condition of the reflection mirror.

BRIEF DESCRIPTION OF THE DRAWINGS

Those and other objects, features and advantages of the presentinvention will become more readily apparent from the following detaileddescription when taken in conjunction with the accompanying drawingswherein:

FIG. 1 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a first embodiment of thepresent invention;

FIGS. 2( a) to 2(1) are explanatory views for showing a manner of rasterscanning, which is conducted within the image displaying apparatusdescribed in FIG. 1 mentioned above;

FIG. 3 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a second embodiment of thepresent invention;

FIG. 4 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a third embodiment of thepresent invention;

FIG. 5 is an explanatory view for showing an example of the structuresof a light receiving member shown in FIG. 4;

FIG. 6 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a fourth embodiment of thepresent invention;

FIGS. 7( a) to 7(o) are timing chart for showing the operation of eachof portions building up the image displaying apparatus shown in FIG. 6;

FIG. 8 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a fifth embodiment of thepresent invention; and

FIG. 9 is a function block diagram for showing the inner structures of alight source driver portion, being included in each of an R video signalconverter portion, a G video signal converter portion and a B videosignal converter portion, respectively, which are shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments according to the present invention will befully explained by referring to the attached drawings.

FIG. 1 is a function block diagram for showing the entire structures ofan image displaying apparatus, according to a first embodiment of thepresent invention.

The image displaying apparatus mentioned above comprises, as shown inFIG. 1, a MEMS resonance mirror (hereinafter, being described as “micromirror”) 1, a mirror driving/holding mechanism 3, a mirror driverportion or unit 5, a mirror drive controller portion or unit 7, a lightsource 9, and a beam light producer lens 11. In addition to thosementioned above, the image displaying apparatus mentioned above furtheralso comprises a light source drive controller portion or unit 13, alight source driver portion or unit 15, a light amount integratorportion or unit 17, a first lookup table holder portion or unit(hereinafter, being described as “first LU holder unit”) 19, a RAM 21and an address generator portion or unit 23.

The address generator unit 23 generates a write-in address signal(hereinafter, being described as “W add”) to the RAM 21 upon basis of ahorizontal synchronization signal (hereinafter, being described as “Hsync”) inputted from a first input terminal 25 and a verticalsynchronization signal (hereinafter, being described as “V sync”)inputted from a second input terminal 27. The address generator unit 23outputs the W add generated therein into the RAM 21, so as to designatea memorizing position for a video signal (hereinafter, being describedas “video”) inputted into the RAM 21 from a third input terminal 29,within the RAM 21. With this, the video mentioned above can be storedinto the memory location within the RAM 21, which is designated by the Wadd.

The address generator unit 23 further inputs therein a horizontaldirection vibration reference signal (hereinafter, being described as “Hstart”), i.e., a reference signal for vibration (oscillation) of themicro mirror 1 in the horizontal direction, which is outputted from themirror drive controller unit 7. The address generator unit 23 alsogenerates a vertical direction vibration reference signal (hereinafter,being described as “V start”), i.e., a reference signal for vibration(or, oscillation) of the micro mirror 1 in the vertical direction, uponbasis of the H start mentioned above, so as to output that V start tothe mirror drive controller unit 7. In this case, it is also possible tosynchronize the timing for generating the V start with the timing ofinputting the V sync from the second input terminal 27 to the addressgenerator unit 23. The address generator unit 23, in synchronism withthe inputting timing of the H start and the generating/outputting timingof the V start, generates a display position (i.e., coordinates); inother words, a laser diode address signal (hereinafter, being describedas “LD Address”) indicative of a specific pixel of video informationduring a raster scanning (actually, it can be defined by a specific timewithin a time period when the raster scanning is conducted). And, itoutputs that LD Address to the light source drive controller unit 13.

This LD Address is a signal, being necessary for drive (ON/OFF) timingof a semiconductor laser, e.g., the light source 9, and for the drivetiming of the micro mirror 1; thus, for controlling the vibration (or,oscillation) timing in the horizontal direction and the vibration (or,oscillation) timing in the vertical direction. With this LD Address,driving (ON/OFF) of the light source (e.g., the semiconductor laser) 9is controlled through the light source drive controller unit 13 and thelight source driver unit 15, and also through the mirror drivecontroller unit 7 and the mirror driver unit 5, the vibration (or,oscillation) in the horizontal direction and the vibration (or,oscillation) in the vertical direction of the micro mirror 1 can becontrolled. In other words, through the raster scanning conductedthrough the ON/OFF drive of the light source 9 and the vibrations in two(2) axial directions of the micro mirror 1, a projection image orpicture in relation to original image information can be formed on ascreen. And, within that projection image, a brightness is adjusted atthe position (e.g., the pixel) on the plane coordinates (X,Y),corresponding to the LD Address mentioned above, upon basis of a LDvideo outputted from the RAM 21 by an R Address, which will be explainedlater. LD Address, R Address and LD Address will be mentioned later, indetails thereof.

The address generator unit 23 generates the R Address, as well as,generation of the LD Address mentioned above, in synchronism with thetiming for inputting the H start and the timing forgenerating/outputting the V start. That R Address is an address signalfor reading out the video stored in the Address (e.g., the memorylocation) corresponding to the LD Address within the RAM 21. That RAddress is outputted from the address generator unit 23 into the RAM 21.

The RAM 21 inputs the video from the third input terminal and the WAddress from the address generator unit 23. And, it stored that video atthe memory location corresponding to the W Address, within the RAM 21.The RAM 21, while inputting the R Address from the address generatorunit 23, also outputs the video, which is stored at the memory locationcorresponding to that R Address, to the light source drive controllerunit 13, as the LD video mentioned above, i.e., the signal for drivingthe laser diode, or the light source 9.

The light source drive controller unit 13 inputs the LD Address from theaddress generator unit 23 and the LD video from the RAM 21,respectively. And, it obtains an amplification factor fitting to that LDAddress and amplifies that LD video by the amplification factorobtained; thereby generating LD AMP, i.e., a signal for driving thelaser diode, or the light source 9, and it also outputs that LD AMPgenerated to the light source driver unit 15.

The light source driver unit 15 drives the light source 9, upon basis ofthe LD AMP mentioned above, which is outputted from the light sourcedrive controller unit 13. Thus, the light source driver unit 15 turnsON/OFF electricity supplies from an electric power source to the lightsource 9, and in particular, when the supply of electricity is ON fromthe electric power source to the light source 9, it supplies an electricpower, being amplified by the amplification factor based on the LD AMPmentioned above, to the light source 9. The driving electric power to besupplied with the light source 9 is adjusted in such a manner, by thelight source driver unit 15, that it is relatively small when scanningon both end portions in the horizontal direction and in the vicinitythereof or that it is relatively large when scanning at a centralportion in the horizontal direction and in the vicinity thereof, duringwithin the raster scanning. Also, during within the raster scanning, thelight source driver unit 15 adjusts the driving electric power to besupplied with the light source 9, such that it becomes large whenscanning a pixel area or region of a relatively bright color, such as, awhite color or a warm color, for example, while it becomes small whenscanning a pixel area or region of a relatively dark color, such as, ablack color or a cold color, for example.

In the present embodiment, as the light source 9 is applied a laserlight source, which can irradiate a beam-like light and modulate anamount of lights therefrom at high speed, easily. However, it is ofcourse that the light source 9, according to the present invention,should not be restricted only to the laser light source. For example, inthe place of the laser light source may be applied any one of thefollowing light sources, such as, LED (light emitting diode), anultrahigh-pressure mercury lamp, a electrode-less lamp, etc., forexample, together with an optical part for condensing the lightsirradiated from that light source and/or a light modulator part of thelight amount. The light source 9, as was mentioned above, is turnedON/OFF with the driving electric power supplied from the electric powersource to the light source 9, under the control of the light sourcedrive controller unit 13, and in particular, when the driving electricpower is ON, it is driven by the light source driver unit 15, whichamplifies and output that driving electric power in the manner mentionedabove; i.e., produces a laser light and outputs it.

The beam light producer lens 11, upon receipt of the laser light fromthe light source 9, produces a laser beam light, and it emits that laserbeam light towards the micro mirror.

The light amount integrator unit 17 obtains a total amount of lightemission of the laser light irradiated from the light source 9 towardsthe beam light producer lens 11, within a predetermined referencetime-period. For example, if reproducing the video information for 60frames during one (1) second (within the reference time-period), as theprojection image on the screen by the raster scanning, then the lightamount integrator unit 17 accumulates or integrates the electric energyfor each frame, which is supplied from the electric power source to thelight source through the light source driver unit 15, until elapsing one(1) second, i.e., completing the raster scanning for 60 frames. Fromthis integrated value of the driving electric power can be calculatedthe total amount of light emission of the light source 9. Within theintegrated value data mentioned above is the data of driving electricpower amount per a pixel, i.e., data of light emission amount. Whenobtaining the data of integrated value about the light emission amount,the light amount integrator unit 17 produces a histogram of that lightemission amount (i.e., data of integrated value of the driving electricpower), and outputs that histogram to the first LUT holder unit 19.

The first LUT holder unit 19 accumulates or integrates the histograms,each of which is outputted from the light amount integrator unit 17every time when the predetermined reference time-period passes. Thehistograms of the light emission amount per each the referencetime-period, which are accumulated within the first LUT holder unit 19,build up history data of the past, indicating the manners, such as, whatis the temperature distribution on the micro mirror 1 and/or how thetemperature is changing on the micro mirror 1, for example. The firstLUT holder unit 19 outputs the above-mentioned past history data, whichis stored therein, to the mirror drive controller unit 7, responding toa read-out request from that mirror drive controller unit 7.

The mirror drive controller unit 7, as well as, outputting the H startmentioned above to the address generator unit 23, also inputs the Vstart mentioned above, which is outputted from the address generatorunit 23. The mirror drive controller unit 7, reading out the pasthistory data in relation to temperature changes of the micro mirror 1,which is stored for each of predetermined reference time zones, from thefirst LUT holder unit 19, also assumes or estimates, what will be thetemperature of the micro mirror 1 at the present of time, upon basis ofthe past history data that is read out. And, it makes up the estimatedtemperature of the micro mirror 1 to be the temperature P temp of themicro mirror at the present time point.

Herein, since the temperature P temp of the micro mirror 1 is affectedor influenced by brightness/darkness of each pixel included in each ofthe frames, then the temperature P temp mentioned above links with thechange of the above-mentioned LD video to be outputted from the RAM 21to the light source drive controller unit 13. This is because of thefact that, depending upon a material building up the micro mirror 1, aportion of the laser beam lights incident upon the micro mirror 1, notbeing reflected thereon, but absorbed to turn into heats therein, anddepending upon the temperature characteristics of the material buildingup this micro mirror 1, the vibration (or, oscillation) conditions ofthe micro mirror 1 are changed, in the horizontal direction and thevertical direction.

The mirror drive controller unit 7 selects H Freq, H AMP and H phase,which are most suitable for obtaining the P temp mentioned above, amongplural numbers of vibration (or, oscillation) frequencies H freq, pluralnumbers of vibration (or, oscillation) amplitudes H AMP, and pluralnumbers of vibration (or, oscillation) phases H phas; i.e., thepredetermined vibration (or, oscillation) conditions in the horizontal(H) direction, being necessary for setting up a value of temperature ofthe micro mirror 1 at a predetermined value. At the same time of this,upon basis of the H start and the V start mentioned above, the mirrordrive controller unit 7 selects V Freq, V AMP and V phase, which aremost suitable for obtaining the P temp mentioned above, among pluralnumbers of vibration (or, oscillation) frequencies V freq, pluralnumbers of vibration (or, oscillation) amplitudes V AMP, and pluralnumbers of vibration (or, oscillation) phases V phas; i.e., thepredetermined vibration (or, oscillation) conditions in the vertical (V)direction, being necessary for setting up a value of temperature of themicro mirror 1 at a predetermined value.

The mirror drive controller unit 7 outputs those H Freq, H AMP, H phas,V Freq, V AMP, and V phas mentioned above to the mirror driver unit 5.

The mirror driver unit 5, when inputting those H Freq, H AMP, H phas, VFreq, V AMP, and V phas mentioned above, from the mirror drivecontroller unit 7, produces H drive and V drive upon those signals,respectively; i.e., a mirror driving signal for vibrate (or, oscillate)the micro mirror 1 in the horizontal (H) direction and a mirror drivingsignal for vibrate (or, oscillate) the micro mirror 1 in the vertical(V) direction. The mirror driver unit 5 outputs the mirror drivingsignals, e.g., H drive and V drive, to the mirror driving/holdingmechanism 3. The mirror driving/holding mechanism 3 is made up with ahorizontal (H) direction driving/holding mechanism 3 a, for holding themicro mirror 1 to freely vibrate (or, oscillate) in the horizontal (H)direction, and a vertical (V) direction driving/holding mechanism 3 b,for holding the micro mirror 1 to freely vibrate (or, oscillate) in thevertical (V) direction. In such mirror driving/holding mechanism 3, avibration speed of the micro mirror 1 in the horizontal (H) direction,by means of the horizontal (H) direction driving/holding mechanism 3 a,is set at a value larger than the vibration speed of the micro mirror 1in the vertical (V) direction, by means of the vertical (V) directiondriving/holding mechanism 3 b. For this reason, after repeating thevibration of micro mirror 1 in the H direction, a several number oftimes thereof, the vibration thereof in the V direction is conductedonly one (1) time.

For example, when displaying the image information corresponding to (640pixels×480 lines) of VGA (Video Graphics Array) at a renewal speed of 60Hz (i.e., displaying the video information for 60 frames during one (1)second), within the image displaying apparatus shown in FIG. 1, forexample, there can be established the following relationship, i.e., thevibration (or, oscillation) number of the micro mirror 1 in the Hdirection is equal to 15 KHz or more than that, and the vibration (or,oscillation) number thereof in the V direction is equal to 30 KHz ormore than that. In other words, during a half (½) cycle of the vibration(or, oscillation) of the micro mirror 1 in the V direction, thevibration (or, oscillation) of the micro mirror 1 occurs in the Hdirection occurs, 250 times or more than that. Hereinafter, explanationwill be made, upon assumption that the micro mirror 1 vibrates (or,oscillates) three (3) times in the H direction, during when it vibrates(or, oscillates) only one (1) time in the V direction, for easilyunderstanding thereof.

Within the mirror driving/holding mechanism 3, when the H drive isoutputted from the mirror driver unit 5, the horizontal (H) directiondriving/holding mechanism 3 a vibrates the micro mirror 1 in thehorizontal (H) direction, upon the H drive, and when the V drive isoutputted from the mirror driver unit 5, the vertical (V) directiondriving/holding mechanism 3 b vibrates the micro mirror 1 in thevertical (V) direction. Thus, the mirror driving/holding mechanism 3holds the micro mirror 1 to be vibrated in two (2) directions (i.e., thedirection of H axial and the direction of V axial), freely,corresponding to the H drive and the V drive, which are outputted fromthe mirror driver unit 5.

The micro mirror 1 is made, mainly, of a material, such as, silicon, forexample, and as was mentioned previously, it is not able to reflect allor the entire beam lights incident thereupon (i.e., the reflectivitythereof is not 100%). Though a very little, for example, about 10% ofthe beam lights incident thereupon are absorbed into the micro mirror 1,and due to this fact the micro mirror generates heats therein. The micromirror 1 receives thereupon the laser lights from the light source 9,which are condensed to be beam-like through the beam light producer lens11, and is vibrated in the horizontal (H) direction by means of thehorizontal (H) direction driving/holding mechanism 3 a and in thevertical (V) direction by means of the vertical (V) directiondriving/holding mechanism 3 b, respectively.

With this, the laser beam light reflected upon the micro mirror 1 isirradiated upon a display area of the video information, which is shownby a reference numeral on the screen, and thereby achieving the rasterscanning along a locus, as shown by a broken line 33. However, on anaxis, in parallel with a side of the display area 31 in the verticaldirection thereof, are plotted times t_(v) (v₀, v₁, v₂, v₃, v₄, v₅)relating to the vibration (or, oscillation) of the micro mirror 1 in thevertical (V) direction, and on an axis, in parallel with a side of thedisplay area 31 in the horizontal direction thereof, are plotted timet_(h) (h₀, h₁, h₂, h₃, h₄, h₅), respectively. The locus 33 of rasterscanning of the laser beam light mentioned above, starting from a pointpositioning near to an upper end of a center line h₂ along with thevertical direction within the above-mentioned display area 31, passesthrough an intersecting point (t_(v),t_(h))=(v₀,h₄) between a segmentv₀, being in parallel with the axis t_(h), and a segment h₄, being inparallel with the axis t_(v), and also through an intersecting point(t_(v),t_(h))=(v₁,h₀) between a segment v₃, being in parallel with theaxis t_(h), and a segment h₀, being in parallel with the axis t_(h).And, the locus 33 of raster scanning also passes through, anintersecting point (t_(v),t_(h))=(v₂,h₄) between a segment v₂, being inparallel with the axis t_(h), and a segment h₄, through an intersectingpoint (t_(v),t_(h))=(v₃,h₀) between a segment v₃, in parallel with theaxis t_(h), and a segment h₀, and through an intersecting point(t_(v),t_(h))=(v₄,h₄) between a segment v₃, being in parallel with theaxis t_(h), and a segment h₄, too. And, further, the locus 33 of rasterscanning also passes through an intersecting point (t_(v),t_(h))=(v₅,h₀)between a segment v₅, being in parallel with the axis t_(h), and asegment h₀, and through an intersecting point between a side at a lowerend of the display area 31 and the center line h₂, too.

Thus, in the raster scanning mentioned above, the vibration (or,oscillation) of the micro mirror 1 generates three (3) times, in the Hdirection, during a half cycle of the vibration (or, oscillation) of themicro mirror 1 in the V direction thereof.

FIGS. 2( a) to 2(1) are explanatory views for showing the condition ofthe raster scanning, which is conducted within the image displayingapparatus described in FIG. 1.

In FIGS. 2( a) to 2(1), in particular, the condition 1 shown in FIG. 2(a) shows an ideal condition of the raster scanning, wherein the rasterscanning stars from a point positioning near to the upper end of thecenter line h₂, passing through the intersecting point(t_(v),t_(h))=(v₀,h₄), the intersecting point (t_(v),t_(h))=(v₁,h₀), theintersecting point (t_(v),t_(h))=(v₂,h₄), the intersecting point(t_(v),t_(h))=(v₃,h₀) the intersecting point (t_(v),t_(h))=(v₄,h₄) andthe intersecting point (t_(v),t_(h))=(v₅, h₀), and reaches to theintersecting point between the side at the lower end of the display area31 and the center line h₂.

Under the condition that the driving (or, oscillating) condition foreach of the mirrors mentioned above is fixed, i.e., H AMP, H Freq, Hphas, V AMP, V Freq, and V phas, to be set up within the mirror drivecontroller unit 7, an amount of the laser beam light to be incident uponthe micro mirror varies, and accompany with that, when the temperature Ptemp of the micro mirror 1 is changed, there is generated a possibilitythat the raster scanning cannot be carried out appropriately. Under thecondition 2 shown in FIG. 2( b), the locus 33 of the raster scanningdoes not reach to the intersecting point (t_(v),t_(h))=(v₀,h₄), theintersecting point (t_(v),t_(h))=(v₂,h₄) and the intersecting point(t_(v),t_(h))=(v₄,h₄), but it reaches from the position near to theupper end of the center line h₂, i.e., the starting point of the rasterscanning, up to an intersecting point between a side at the lower end ofthe display area 31 and the center line h₂. Also, under the condition 3shown in FIG. 2( c), it does not reach to even the intersecting point(t_(v),t_(h))=(v₁,h₀), the intersecting point (t_(v),t_(h))=(v₃,h₀) andthe intersecting point (t_(v),t_(h))=(v₅,h₀), further, in addition tothe respective intersecting points where it does not reach to under thecondition 2 shown in FIG. 2( b), but it reaches from the position nearto the upper end of the center line h₂, i.e., the starting point of theraster scanning, up to the intersecting point between the side at thelower end of the display area 31 and the center line h₂.

Thus, either one of the condition 2 or the condition 3 indicates thatthe amplitude of the vibration (or, oscillation) is short orinsufficient, in particular, in the horizontal (H) direction.

Next, under the condition 4 shown in FIG. 2( d), the locus 33 of theraster scanning 33 reaches from the position near to the upper end ofthe center line h₂ up to the intersecting point between the side at thelower end of the display area 31 and the center line h₂, exceeding theintersecting point (t_(v),t_(h))=(v₀,h₄), the intersecting point(t_(v),t_(h))=(v₁,h₀), the intersecting point (t_(v),t_(h))=(v₂,h₄) theintersecting point (t_(v),t_(h))=(v₃,h₀), the intersecting point(t_(v),t_(h))=(v₄,h₄) and the intersecting point (t_(v),t_(h))=(v₅,h₀),greatly.

Thus, the condition 4 indicates that the amplitude of the vibration (or,oscillation) is excessive, in particular, in the horizontal (H)direction of the micro mirror 1.

Next, under the condition 5 shown in FIG. 2( e), the locus of the rasterscanning 33 goes beyond the intersecting point (t_(v),t_(h))=(v₀,h₄) andthe intersecting point (t_(v),t_(h))=(v₁,h₀), greatly, where it wouldintrinsically intersects with them, since the amplitude of the vibration(or, oscillation) is excessive in the horizontal (H) direction of themicro mirror 1, within a time region from the position near to the upperend of the center line h₂, i.e., the starting point of the rasterscanning, up to the position where it intersects with the section v₀,and also in a time region from the position where it intersects with thesection v₀ up to when it intersects with the section v₁. Also, within atime region from the position where it intersects with the section v₄ tothe position where it intersects with the section v₅, since theamplitude of the vibration (or, oscillation) is short or insufficient inthe horizontal (H) direction of the micro mirror 1, the locus of theraster scanning 33 does not reach to the intersecting point(t_(v),t_(h))=(v₄,h₄) and the intersecting point (t_(v),t_(h))=(v₅,h₀),greatly, where it would intrinsically intersects with them. The timeregion where the amplitude of the vibration (or, oscillation) isappropriate in the value thereof is only a time region from the positionwhere the locus of the raster scanning 33 intersects with the section v₂up to the position where it intersects with the section v₃.

Next, under the condition 6 shown in FIG. 2( f), the locus of the rasterscanning 33 does not reach to the intersecting point(t_(v),t_(h))=(v₀,h₄) and the intersecting point (t_(v),t_(h))=(v₁,h₀),greatly, where it would intrinsically intersects with them, since theamplitude of the vibration (or, oscillation) is short or insufficient inthe horizontal (H) direction of the micro mirror 1, within the timeregion from the position near to the upper end of the center line h₂,i.e., the starting point of the raster scanning, up to the positionwhere it intersects with the section v₀, and also in the time regionfrom the position where it intersects with the section v₀ up to when itintersects with the section v₁. Also, within the time region from theposition where it intersects with the section v₄ to the position whereit intersects with the section v₅, since the amplitude of the vibration(or, oscillation) is excessive in the horizontal (H) direction of themicro mirror 1, the locus of the raster scanning 33 goes beyond to theintersecting point (t_(v),t_(h))=(v₄,h₄) and the intersecting point(t_(v),t_(h))=(v₅,h₀), greatly, where it would intrinsically intersectswith them. The time region where the amplitude of the vibration (or,oscillation) is appropriate in the value thereof is only a time regionfrom the position where the locus of the raster scanning 33 intersectswith the section v₂ up to the position where it intersects with thesection v₃.

Therefore, in case where the locus 33 of the raster scanning is in thecondition 2 shown in FIG. 2( b) and the condition 3 shown in FIG. 2( c),the mirror drive controller unit 7 adjusts the H AMP, i.e., the controlsignal for the vibration (or oscillation) amplitude, which is outputtedto the mirror driver unit 5, so as to increase the amplitude of thevibration (or oscillation) in the horizontal (H) direction of the micromirror 1, thereby controlling it under the condition 1 shown in FIG. 2(a). Also, in case where the locus 33 of the raster scanning is in thecondition 4 shown in FIG. 2( d), then the mirror drive controller unit 7adjusts the H AMP, i.e., the control signal for the vibration (oroscillation) amplitude, which is outputted to the mirror driver unit 5,so as to reduce the amplitude of the vibration (or oscillation) in thehorizontal (H) direction of the micro mirror 1, thereby controlling itunder the condition 1 shown in FIG. 2( a).

Further, in the case where the locus 33 of the raster scanning is in thecondition 5 shown in FIG. 2( e) and the condition 6 shown in FIG. 2( f),the mirror drive controller unit 7 adjusts the H AMP, i.e., the controlsignal for the vibration (or oscillation) amplitude, which is outputtedto the mirror driver unit 5, so as to increase or reduce the amplitudeof the vibration (or oscillation) in the horizontal (H) direction of themicro mirror 1, appropriately, and thereby controlling it under thecondition 1 shown in FIG. 2( a).

However, the mirror drive controller unit 7 may adjust the H Freq, i.e.,the control signal for the vibration (or oscillation) frequency, in theplace of the control signal for the vibration (or oscillation)amplitude, so as to obtain increasing/decreasing of the amplitude of thevibration (or oscillation) in the horizontal (H) direction of the micromirror 1. Irrespective of conduction of increasing/decreasing theamplitude of the vibration (or oscillation) in the horizontal (H)direction of the micro mirror 1 by the variable adjustment of H AMP orthe adjustment of H Freq, however an adjustment is made upon the controlsignal, V phas for the vibration (or oscillation) phase, in synchronismwith those adjustments, so as to produce the vibration reference signalof horizontal direction mentioned above, i.e., H start, and thereby alaser light is irradiated from the light source 9, upon basis of adrover signal for the light source 9 fitting to that amplitude, i.e., LDvideo, while controlling the amplitude of vibration (or oscillation) inthe horizontal (H) direction of the micro mirror 1, to be constant.

However, the case of the condition 7 shown in FIG. 2( g) shows that itis under the ideal condition of the raster scanning, similar to the caseof the condition 1 shown in FIG. 2( a), and the case of the condition 8shown in FIG. 2( h) shows that the amplitude of vibration (oroscillation) of the micro mirror 1 is short or insufficient in thevertical (V) direction. Next, the case of the condition 9 shown in FIG.2( i) shows that the amplitude of vibration (or oscillation) isexcessive in the vertical (V) direction, and the case of the condition10 shown in FIG. 2( j) shows that the locus 33 of the raster scanningcomes to be long in the cycle of a sine wave, as it goes down in thefigure. Next, the case of the condition 11 shown in FIG. 2( k) showsthat, on the contrary to the case of the condition 10 shown in FIG. 2(j), the locus 33 of the raster scanning comes to be short in the cycleof the sine wave, as it goes down in the figure.

Further, the case of the condition 12 shown in FIG. 2( l) shows thecondition of combining the condition, which is similar to the condition6 shown in FIG. 2( f), and the condition, which is similar to thecondition 11 shown in FIG. 2( k), wherein the amplitude of vibration (oroscillation) of the micro mirror 1 changes both, in the horizontal (H)direction and also in the vertical (V) direction.

As was explained in the above, according to the first embodiment of thepresent invention, in case where there is an interrelation orcorrelation between the temperature of the micro mirror 1 and theamplitude of the vibration (or oscillation) in the horizontal (H)direction, which the micro mirror 1 can take, the locus 33 of the rasterscanning is controlled, so as to be in the condition 1 shown in FIG. 2(a), through adjusting the H AMP or H Freq, such that the temperature ofthe micro mirror 1 comes to be a preset value of temperature whiledetermining the temperature of the micro mirror 1 upon basis of antamount of the laser beam emitted from the light source 9, and therebyenabling the projection display within the display area or region on thescreen, with stability.

Within the first embodiment of the present invention mentioned above,although optimization is made upon the driving (oscillating) conditionof the micro mirror (i.e., H AMP, H Freq, H phas, VAMP, V Freq and Vphas), which is determined by the mirror drive controller unit 7,depending upon the temperature of the micro mirror 1, however driving ofthe micro mirror 1 may be also stabilized, through controlling thetemperature of the micro mirror 1, by cooling down the micro mirror 1,compulsively. Or, without adjusting the H AMP and the H Freq, it may bealso treated with, for example, changing the phase of staring theradiation of the laser beam light upon basis LD video.

However, a turbulence is generated in the synchronization, whenadjusting the H Freq while fixing the V Freq, but it is also possible toobtain the synchronization between the vibration in the vertical (V)direction and the vibration in the horizontal (H) direction, i.e.,stopping the vibration (or oscillation) in the horizontal (H) direction,in the vibration (or oscillation) in the vertical (V) direction, duringthe time when the vibration (or oscillation) direction is reversed, andstarting the vibration in the horizontal (H) direction, again, insynchronism with the timing when staring the vibration (or oscillation)in the vertical (V) direction. Further, upon adjusting the H Freq, H AMPand H phas, while conducting the raster scanning, when the time isdifferent when it passes through each of the pixels, then it is alsopossible to increase/decrease the intensity of the laser light outputtedfrom the light source 9, so as to bring an accumulated or integratedamount of the lights for each of the pixels to be constant.

FIG. 3 is a function block diagram for showing the entire structures ofthe image displaying apparatus, according to a second embodiment of thepresent invention.

The image displaying apparatus shown in FIG. 3 differs from the imagedisplaying apparatus (e.g., according to the first embodiment of thepresent invention) shown in FIG. 1, in the structures thereof, inparticular, in the following aspects: i.e., removing the light amountintegrator unit 17 and the first LUT holder unit 19 from the structuresshown in FIG. 1, and also adding a temperature detector unit 35, adetected temperature value integrator unit 37, and a second lookup tableholder unit (hereinafter, being described as “second LUT holder unit”)39. However, with the structures shown in FIG. 3, but other than thoseare same to those shown in FIG. 1, and therefore will be omitted theexplanation about the details thereof.

In FIG. 3, the temperature detector unit 35 is disposed in vicinity ofthe micro mirror 1, and it detects the temperature of the micro mirror1, so as to output an electric signal depending on the value oftemperature detected, to the detected temperature value integrator unit37. The detected temperature value integrator unit 37, inputting thetemperature detection signal outputted from the temperature detectorunit 35, obtains accumulated value data of the temperature value of themicro mirror 1 during a reference time-period, which is determined inadvance. For example, if assuming that the video information for 60frames are reproduced through the raster scanning, as the projectionimage on the screen, during 1 second (within the reference time-period),for example, then the detected temperature value integrator unit 37accumulates the temperature value detected for each frame, which isoutputted from the temperature detector unit 35, until when it completesthe raster scanning for 60 frames, after elapsing 1 second.

Within this accumulated data of detected temperature values is includeda temperature value detected for each of the pixels included in each ofthe frames. When obtaining the accumulated data of detected temperaturevalues, the detected temperature value integrator unit 37 produces ahistogram of that accumulate data, and outputs that histogram to thesecond LUT holder unit 39.

The second LUT holder unit 39 stores therein the histograms of theaccumulated data mentioned above, each of which is outputted from thedetected temperature value integrator unit 37 each time when passing thepredetermined reference time-period. The histograms of the accumulateddata for each reference time-period, which are stored within the secondLUT holder unit 39, function as the history data of the past indicativeof a manner of temperature distribution on the micro mirror 1 or amanner of changing of temperature on the micro mirror 1. The second LUTholder unit 39 outputs the history data of the past, which are storedtherein, to the mirror drive controller unit 7, responding to a requestlo for reading out the data made from that mirror drive controller unit7. Further, the mirror drive controller unit 7 determines the driving(or oscillating) condition for the micro mirror 1, as was mentionedabove, in accordance with the processing steps, being similar to thosewithin the first embodiment of the present invention shown in FIG. 1.

Therefore, also within the present embodiment, it is possible to controlthe locus 33 of the raster scanning, by the vibration (or oscillation)of the micro mirror 1, so that it approaches to the ideal condition ofthe raster scanning shown in FIG. 2( a).

As was mentioned above, according to the second embodiment of thepresent invention, as well as, detecting the change of temperature onthe micro mirror 1, accurately, it is also possible to determine thedriving (or oscillating) condition suitable to the detected change oftemperature on the micro mirror 1, thereby to drive (or oscillate) themicro mirror 1 under a stable condition of obtaining an equal vibrationfrequency or an equal vibration amplitude or an equal vibration phase.

FIG. 4 is a function block diagram for showing the entire structures ofthe image displaying apparatus, according to a third embodiment of thepresent invention.

The image displaying apparatus shown in FIG. 4 differs from the imagedisplaying apparatus (e.g., according to the first embodiment of thepresent invention) shown in FIG. 1, in particular, by newly adding aphoto receiving member 41, a photo/eclectic converter element 43 and acondition detector portion 45, in the structures thereof. However, sincethe structures shown in FIG. 4, but other than those mentioned above,are same to those shown in FIG. 1, and therefore in this FIG. 4, thesame reference numerals are attached for those shown in FIG. 1, but theexplanation will be omitted about the details thereof.

In FIG. 4, the photo receiving member 41 is a line-like member. Thisphoto receiving member 41 is disposed along the axis t_(v) in FIG. 4, ata position at one of the ends of the vibration (or oscillation) in thehorizontal (H) direction in the case where the locus 33 of the rasterscanning is in the ideal condition (i.e., the condition like that shownin FIG. 2( b)), i.e., at least a part of an area or region, upon whichthe lights reflected on the micro mirror 1 can radiate (or project)upon, but not interrupting or obstructing them. Also, as was mentionedabove, the axis t_(v) indicates the direction of the vibration (oroscillation) of the micro mirror 1 in the vertical (V) direction. Thephoto receiving member 41, receiving the reflection lights from themicro mirror 1, reflects that reflection light received thereupon, orrefracts them, into a specific direction. The photo receiving member 41will be mentioned in more details thereof, later.

The photo/eclectic converter element 43 is provided at a position forreceiving the lights, which are reflected or refracted from the photoreceiving member 41. The photo/eclectic converter element 43 receivesthe lights, which are reflected or refracted from the photo receivingmember 41, at timing when the vibration (or oscillation) in thehorizontal (H) direction mentioned above intersects with the positionwhere the photo receiving member 41 is disposed as shown in FIG. 4, onthe locus 33 of the raster scanning. And, due to the lights received isgenerated electromotive force, and with that electromotive force, apredetermined electric signal PD1 is outputted to the condition detectorportion 45. In other words, the photo/eclectic converter element 43outputs the electric signal PD1 mentioned above, intermittently, at thetiming when the above-mentioned vibration (or oscillation) in thehorizontal (H) direction intersects the photo receiving member 41.

The condition detector portion 45, receiving the electric signal PD1from the photo/eclectic converter element 43, detects the operatingcondition of the micro mirror 1, upon basis of that electric signal PD1.Thus, the condition detector portion 45 obtains the vibration (oroscillation) frequency data, the vibration (or oscillation) amplitudedata and the vibration (or oscillation) phase data indicative of theoperating condition of the micro mirror 1, through measurement on aninterval of output timing of the electric signal PD1, which is outputtedintermittently. The condition detector portion 45 outputs a signal LDout, including the vibration (or oscillation) frequency data, thevibration (or oscillation) amplitude data and the vibration (oroscillation) phase data therein, to a comparator unit 47.

The comparator unit 47 inputs the above signal LD out, which isoutputted from the condition detector portion 45, and the signal LDaddress mentioned above, which is outputted from the address generatorunit 23. As was mentioned previously, the signal outputted from theaddress generator unit 23 is the signal, being necessary for controllingthe driving (ON/OFF) timing of the semiconductor laser, a being thelight source 9, and the timing for driving the micro mirror 1, e.g., thevibration (oscillation) timing in the horizontal direction and thevibration (oscillation) timing in the vertical direction thereof. Fromthat signal LD Address, it is possible to detect the drive (oroscillate) condition, being appropriate for the micro mirror 1, i.e., HFreq, H AMP and H phas.

The comparator unit 47 compares the above signal LD out and the LDAddress, and outputs the result of that comparison to the mirror drivecontroller unit 7. The mirror drive controller unit 7 adjusts the drive(or oscillate) condition of the micro mirror 1, e.g., H Freq, H AMP andH phas, V Freq, V AMP and V phas, to be outputted to the mirror driverunit 5, again, upon basis of the comparison result mentioned above,which is outputted from the comparator unit 47.

FIG. 5 is a view for showing an example of the structures of the photoreceiving member 41 shown in FIG. 4.

As is shown in FIG. 5, the photo receiving member 41 is made from anoptical fiber having an about rectangular parallelepiped (or,parallelopipedon) configuration, as a whole thereof. Thus, the photoreceiving member 41 has a half-mirror construction, i.e., including alight receiving surface, for receiving the lights thereon reflected onthe micro mirror 1, which is in a plane-like and rectangularconfiguration thereof, and also a light transmission/diffusion body inan inside thereof, and a mirror surface.

However, upon the fact that the locus 33 of the raster scanningmentioned above passes through the photo receiving member 41, inaddition to H AMP, H Freq and H phas, indicating the vibration (oroscillation) condition in the horizontal (H) direction, the conditiondetector portion 45 also obtains V AMP, V Freq and V phas, indicatingthe vibration (or oscillation) condition in the vertical (V) direction,as the vibration (or oscillation) frequency data, the vibration (oroscillation) amplitude data and the vibration (or oscillation) phasedata, indicating the operating condition of the micro mirror 1, throughthe photo receiving member 41 and the photo/eclectic converter element43.

As was explained in the above, according to the third embodiment of thepresent invention, with adjusting the vibration (or oscillation)condition of the micro mirror 1, in such a manner that the timing, whenthe lights reflected upon the micro mirror 1 (i.e., the locus 33 of theraster scanning) intersects the photo receiving member 41, comes into anappropriate vibration (or oscillation) frequency, an appropriatevibration (or oscillation) amplitude and an appropriate vibration (oroscillation) phase, it is possible to drive (or oscillate) the micromirror 1, with stability, under the driving (or oscillating) conditionsuitable to the temperature of the micro mirror 1.

Also, even in case where the locus 33 of the raster scanning mentionedabove moves along a longitudinal direction of the photo receiving member41 while changing the vibration (or oscillation) direction on the photoreceiving member 41, since the condition detector portion 45 can detectthe change of that vibration (or oscillation) through the photoreceiving member 41 and the photo/eclectic converter element 43, thereis no necessity of providing that photo/eclectic converter element 43,respectively, at plural numbers of places on the photo receiving member41, where the vibration (or oscillation) direction can be changed on thelocus 33 of the raster scanning, and therefore it is possible to achievereduction of costs of the parts thereof, easily.

With the third embodiment of the present invention, though theexplanation was explained so that the photo receiving member 41 isdisposed at least in a part of the area where the reflection lights fromthe micro mirror 1 can be irradiated (or projected), however, it is ofcourse that the manner of disposition of the photo receiving member 41should not be limited to that manner mentioned above. Even when theposition of disposing the photo receiving member 41 is disposed outsidethe display area or region 31, but there is no problem if the photoreceiving element 41 is disposed in such the manner that the detectionresult can be obtained, same or similar to that obtained in the mannermentioned above.

FIG. 6 is a function block diagram for showing the entire structures ofthe image displaying apparatus, according to a fourth embodiment of thepresent invention.

The image displaying apparatus shown in FIG. 6 differs from the imagedisplaying apparatus shown in FIG. 4, in the structures thereof, inparticular, in the following aspects; i.e., the photo receiving member41 and the photo/eclectic converter element 43, which are shown in FIG.4, are further disposed, in addition to the position where they aredisposed, as was shown in FIG. 4, also at the position, symmetrical withthat position about the center line h₂ of the display area 31, and thatthe condition detector portion 45 detects the operating condition of themicro mirror 1, upon basis of the electric signal PD1, which isoutputted from the photo/eclectic converter element 43 shown at theright-hand side in FIG. 6, and the electric signal PD2, which isoutputted from the photo/eclectic converter element 43 shown at theleft-hand side in FIG. 6. However, since the structures shown in FIG. 6,but other than those mentioned above, are same to those shown in FIG. 4,and therefore in this FIG. 6, the same reference numerals are attachedfor those shown in FIG. 4, but the explanation will be omitted about thedetails thereof.

In such the structures mentioned above, the condition detector portion45, as well as, measuring the distance between output timings of theabove-mentioned two (2) electric signals PD1 and PD2, each beingoutputted, intermittently, from the photo/eclectic converter element 43or 43, respectively, detects presence of the output of the electricsignal mentioned above, thereby obtaining the vibration (or oscillation)frequency data, the vibration (or oscillation) amplitude data and thevibration (or oscillation) phase data, indicating the operatingcondition of the micro mirror 1, and it outputs the signal LD out,including the vibration (or oscillation) frequency data, the vibration(or oscillation) amplitude data and the vibration (or oscillation) phasedata obtained in the above, to the comparator unit 47. In the comparatorunit 47 are compared the signal LD out and the signal LD Address, so asto output the comparison result thereof to the mirror drive controller.The processes thereafter are almost same to those contents, which wereexplained by referring to FIG. 4 in the above, and therefore theexplanation thereof will be omitted herein.

FIGS. 7( a) to 7(o) are timing charts for showing the operation of eachof portions building up the image displaying apparatus shown in FIG. 6mentioned above.

In FIGS. 7( a) to 7(o), in particular, FIG. 7( a) shows a waveform of avibration horizontal direction vibration reference signal, i.e., the Hstart signal, FIG. 7( b) shows a waveform of a laser diode addresssignal, which is outputted from the address generator unit 23 to thecomparator unit 47, i.e., the LD Address signal, respectively. Next,FIG. 7( c) shows a waveform of the H drive signal, which is outputtedfrom the mirror driver unit 5 to the horizontal (H) directiondriving/holding mechanism 3 a of the mirror driving/holding mechanism 3(i.e., the mirror driving signal for driving (or oscillating) the micromirror 1 into the horizontal (H) direction).

Next, FIG. 7( d) shows a waveform of the vibration (or oscillation) ofthe micro mirror 1 in the horizontal (H) direction when the locus 33 ofthe raster scanning is in the ideal condition, as is shown by thecondition 1 in FIG. 2( a), for example, and FIG. 7( e) shows a waveformof the electric signal PD1, which is outputted from one of thephoto/eclectic converter elements 43 to the condition detector portion45, when the locus 33 of the raster scanning is in the condition 1,respectively. Next, FIG. 7( f) shows a waveform of the electric signalPD2, which is outputted from the other of the photo/eclectic converterelements 43 to the condition detector portion 45, when the locus 33 ofthe raster scanning is in the condition 1, and FIG. 7( g) a waveform ofthe LD out signal, which is outputted from the condition detectorportion 45 to the comparator unit 47, when the locus 33 of the rasterscanning is in the condition 1, respectively.

Next, FIG. 7( h) shows a waveform of the vibration (or oscillation) ofthe micro mirror 1 in the horizontal (H) direction when the locus 33 ofthe raster scanning is in the condition 2, which is shown in FIG. 2( b),for example, and FIG. 7( i) a waveform of the electric signal PD1, whichis outputted from one of the photo/eclectic converter elements 43 to thecondition detector portion 45, when the locus 33 of the raster scanningis in the condition 2, respectively. Next, FIG. 7( j) shows a waveformof the electric signal PD2, which is outputted from the other of thephoto/eclectic converter elements 43 to the condition detector portion45, when the locus 33 of the raster scanning is in the condition 2, andFIG. 7( k) a waveform of the LD out signal, which is outputted from thecondition detector portion 45 to the comparator unit 47, when the locus33 of the raster scanning is in the condition 2, respectively.

Next, FIG. 7( l) shows a waveform of the vibration (or oscillation) ofthe micro mirror 1 in the horizontal (H) direction when the locus 33 ofthe raster scanning is in the condition 3, which is shown in FIG. 2( c),for example, and FIG. 7( m) a waveform of the electric signal PD1, whichis outputted from one of the photo/eclectic converter elements 43 to thecondition detector portion 45, when the locus 33 of the raster scanningis in the condition 3, respectively. Next, FIG. 7( n) shows a waveformof the electric signal PD2, which is outputted from the other of thephoto/eclectic converter elements 43 to the condition detector portion45, when the locus 33 of the raster scanning is in the condition 3, andFIG. 7( o) a waveform of the LD out signal, which is outputted from thecondition detector portion 45 to the comparator unit 47, when the locus33 of the raster scanning is in the condition 3, respectively.

As shown in FIG. 7( a) to 7(o), the H start signal is outputted one byone, from the mirror drive controller unit 7 to the address generatorunit 23, at h₀ when the vibration (or oscillation) of the locus 33 ofthe raster scanning reaches to one end of the display area 31 and h₄when it reaches to the other end of the display area 31, respectively.In other words, the H start signal is outputted from the mirror drivecontroller unit 7 to the address generator unit 23, every half cycle ofthe vibration (or oscillation) of the locus 33 of the raster scanning inthe horizontal (H) direction. In FIGS. 7( a) to 7(o), the time-periodfrom rise-up of the H start signal to rise-up of the next coming H startsignal is indicated by 1H.

The LD Address signal rises up after elapsing a constant time delay fromthe rise-up of the H start signal. In FIGS. 7( a) to 7(o), where a firstLD Address signal rises up is at the position indicated by the time h₃,after the position indicated by the time h₄where a first H start signalrises up. Where this first LD Address signal falls down is at theposition, which is indicated by the time h₁, after the time h₃. Next,where a second LD Address signal rises up is at the position indicatedby the time h₁, after the position indicated by the time h₀ where asecond H start signal rises up, and where this second LD Address signalfalls down is at the position indicated by the time h₃, after the timeh₁. Next, where a third LD Address signal rises up is at the positionindicated by the time h₃, after the position indicated by the time h₄where a third H start signal rises up, and where this third LD Addresssignal falls down is at the position indicated by the time h₁, after thetime h₃.

Next, where a fourth LD Address signal rises up is at the positionindicated by the time h₁, after the position indicated by the time howhere a fourth H start signal rises up, and where this fourth LD Addresssignal falls down is at the position indicated by the time h₃, after thetime h₁. Further, where a fifth LD Address signal rises up is at theposition indicated by the time h₃, after the position indicated by thetime h₄ where a fifth H start signal rises up. The H drive signal is asine-wave signal, taking the time between the rise-up of the first Hstart signal and the rise-up of the third H start signal or the timebetween the rise-up of the third H start signal and the rise-up of thefifth H start signal, as one cycle, respectively.

The waveform of the vibration (or oscillation) of the micro mirror 1 inthe horizontal (H) direction shown in FIG. 7( d), as is apparent fromthat figure, can be also shown by the sine-wave, similar to the H drivesignal, and the cycle thereof is also almost same to the cycle of the Hdrive signal. The waveform of the vibration (or oscillation) in thehorizontal (H) direction is shifted from the H drive signal in thephase, i.e., from the time h₂, to the time h₄. In FIG. 7( e), a firstPD1 signal rises up at the time h₁ where the first LD Address signalrises up, and a second PD1 signal falls down at the time h₁ where thesecond LD Address signal rises up. A third PD1 signal rises up at thetime h₁ where the third LD Address signal falls down, and a fourth PD1signal falls down at the time h₁ where the fourth LD Address signalrises up.

In FIG. 7( f), a first PD2 signal falls down at the time h₃ where thefirst LD Address signal rises up, and a second PD2 signal rises up atthe time h₃ where the second LD Address signal falls down. A third PD2signal falls down at the time h₃ where the third LD Address signal risesup, and a fourth PD2 signal rises up at the time h₃ where the fourth LDAddress signal falls down. A fifth PD2 signal falls down at the time h₃where the fifth LD Address signal rises up. In FIG. 7( g), a first LDout signal is in synchronism with the first LD Address signal, a secondLD out signal with the second LD Address signal, a third LD out signalwith the third LD Address signal, a fourth LD out signal with the fourthLD Address signal, and a fifth LD out signal with the fifth LD Addresssignal, respectively.

The waveform of the vibration (or oscillation) of the micro mirror 1 inthe horizontal (H) direction shown in FIG. 7( h) is also in thesine-wave, being similar to the wave of the micro mirror 1 in thehorizontal (H) direction shown in FIG. 7( d); however, the maximum valuein the amplitude thereof is a little bit smaller than that of thewaveform of the vibration (or oscillation) shown in FIG. 7( d).Regarding the phase, it is almost same to that of the waveform of thevibration (or oscillation) shown in FIG. 7( d). Regarding the PD1signals, any one of them rises up at the time ho, and also regarding thePD2 signals, at the time h₄. Further, regarding the LD out signals, thefirst, third and fifth ones rise up at the time h₄, and fall down at thetime h₀, respectively, while the second and forth LD out signals rise upat the time h₄, and fall down at the time h₀, respectively.

And, the waveform of the vibration (or oscillation) of the micro mirror1 in the horizontal (H) direction shown in FIG. 7( l) is also thesine-wave, being similar to the wave of the micro mirror 1 in thehorizontal (H) direction shown in FIGS. 7( d) and 7(h); however, themaximum value in the amplitude thereof is considerably smaller than thatof the waveform of the vibration (or oscillation) shown in FIG. 7( d).Regarding the phase, it is almost same to that of the waveform of thevibration (or oscillation) shown in FIGS. 7( d) and 7(h). Regarding thePD1 signals, PD2 signals, and LD out signals, any one of them is notoutputted.

As was explained in the above, according to the fourth embodiment of thepresent invention, it is possible to adjust the driving (or oscillating)condition of the micro mirror, so as to bring it into the vibration (oroscillation) frequency, the vibration (or oscillation) amplitude and thevibration (or oscillation) phase, being appropriate much more, comparingto the third embodiment of the present invention mentioned above, andthereby enabling to drive (or oscillate) the micro mirror 1, withstability, while determining or setting up the driving (or oscillating)condition of the micro mirror 1 to be high in the accuracy thereof.

FIG. 8 is a function block diagram for showing the entire structures ofthe image displaying apparatus, according to a fifth embodiment of thepresent invention.

The image displaying apparatus shown in FIG. 6 differs from the imagedisplaying apparatus shown in FIG. 4, in the structures thereof, inparticular, in an aspect that, in addition to the light source shown bythe reference numeral 9 and the beam light producer lens shown by thereference numeral 11 in FIG. 4, there are further provided thefollowings; i.e., a light source, which is shown by a reference numeral57, a beam light producer lens, which is shown by a reference numeral59, a light source, which is shown by a reference numeral 61, a beamlight producer lens, which is shown by a reference numeral 63. In FIG.8, the light source 9 functions as the light source for irradiating alaser light of blue color (B), and the beam light producer lens 11,receiving the laser light of the blue (B) color irradiated from thelight source 9 thereupon, produces a laser beam light of the blue color;i.e., being used as the beam light producer lens, for emitting that bluecolor laser beam directing onto the micro mirror 1. Also, the lightsource 57 functions as the light source for irradiating a laser light ofgreen color (G), and the beam light producer lens 59, receiving thelaser light of the green (G) color irradiated from the light source 57thereupon, produces a laser beam light of the green color; i.e., beingused as the beam light producer lens, for emitting that green colorlaser beam directing onto the micro mirror 1. Further, the light source61 functions as the light source for irradiating a laser light of redcolor (R), and the beam light producer lens 63, receiving the laserlight of the red (R) color irradiated from the light source 61thereupon, produces a laser beam light of the red color; i.e., beingused as the beam light producer lens, for emitting that red color laserbeam directing onto the micro mirror 1.

Also, in the image displaying apparatus shown in FIG. 8 are providedthree (3) sets of video signal converter units, i.e., a R (red color)video signal converter unit 51, a G (green color) video signal converterunit 53 and a B (blue color) video signal converter unit 55,corresponding to the three (3) light sources 9, 57 and 61, respectively.Those video signal converter units 51, 53 and 55 are same in thestructures thereof, and each includes the light source drive controllerunit 13, the light source driver unit 15, the light amount integratorunit 17, and the first LUT holder unit 19, which are shown in FIG. 4.Since each unit of those was already mentioned, previously, in thedetails thereof, duplication of explanation thereof will be omitted. Inthis FIG. 8, the R video signal converter unit 51 controls the drivingof the light source 61 (i.e., irradiating the red color laser light),the G video signal converter unit 53 the driving of the light source 57(i.e., irradiating the green color laser light), and the B video signalconverter unit 55 the driving of the light source 9 (i.e., irradiatingthe blue color laser light), respectively. However, since the structuresshown herein, but other than those mentioned above, are same to thoseshown in FIG. 4, and therefore in this FIG. 8, the same referencenumerals are attached for those shown in FIG. 4, but the explanationwill be omitted about the details thereof.

In the structures mentioned above, the R video signal converter unit 51inputs the LD Address from the address generator unit 23, and a kind ofthe LD video from the RAM 21, i.e., R video, respectively. That R videoincludes therein bright/dark information relating to a red color (R)video signal (i.e., information indicating brightness for each pixel inrelation with the red color (R) video signal). The R video signalconverter unit 51 obtains an amplification factor fitting to the LDAddress, so as to amplify the R video at that amplification factorobtained, and thereby producing the LD AMP, i.e., the signal for drivingthe light source 61, and at the same time, it also drives the lightsource 61 with that LD AMP produced. With this, the light amount of thered color laser light irradiated from the light source 61 can bemodulated. The G video signal converter unit 53, similar to that withinthe R video signal converter unit 51, also inputs the LD Address fromthe address generator unit 23, and G video, respectively. That G videoincludes therein bright/dark information relating to a green color (G)video signal (i.e., information indicating brightness for each pixel inrelation with the green color (G) video signal). The G video signalconverter unit 53 obtains an amplification factor fitting to the LDAddress, so as to amplify the G video at that amplification factorobtained, and thereby producing the LD AMP, i.e., the signal for drivingthe light source 57, and at the same time, it also drives the lightsource 61 with that LD AMP produced. With this, the light amount of thegreen color laser light irradiated from the light source 57 can bemodulated. Also, the B video signal converter unit 55, similar to thatwithin the G video signal converter unit 53 and/or the R video signalconverter unit 51, inputs the LD Address from the address generator unit23, and B video, respectively. That B video includes therein bright/darkinformation relating to the blue color (B) video signal (i.e.,information indicating brightness for each pixel in relation with theblue color (B) video signal). The B video signal converter unit 55obtains an amplification factor fitting to the LD Address, so as toamplify the B video at that amplification factor obtained, and therebyproducing the LD AMP, i.e., the signal for driving the light source 9,and at the same time, it also drives the light source 9 with that LD AMPproduced. With this, the light amount of the blue color laser lightirradiated from the light source 9 can be modulated.

The R video signal converter unit 51, the G video signal converter unit53, or the B video signal converter unit 55, in parallel with theprocessing operation mentioned above, produces and stores therein,respectively, a histogram of an amount of light emission per a unit of areference time, i.e., the history data of the past, for showing a mannerof the temperature distribution on the micro mirror 1 and/or a manner ofchanges of the temperature on the micro mirror 1. And, it outputs theabove-mentioned history data of the past stored therein to the mirrordrive controller unit 7, responding to the request of data readout fromthe mirror drive controller unit 7. The mirror drive controller unit 7presumes what the temperature is on the micro mirror 1 at the presenttime, upon basis of the history data, and sets that temperature of themicro mirror 1 presumed, as the temperature P temp on the micro mirror 1at the present time. The following steps of processing are as mentionedpreviously.

FIG. 9 is a function block diagram for showing the internal structuresof the light source driver unit 15 (shown in FIG. 1, FIG. 3, FIG. 4 andFIG. 6), which is included in any one of the R video signal converterunit 51, the G video signal converter unit 53 and the B video signalconverter unit 55 shown in FIG. 8.

The light source driver unit 15 mentioned above comprises therein, asshown in FIG. 9, four (4) sets of PWM (i.e., Pulse Width Modulation)circuit 67, 69, 71 and 73, four (4) sets of pulse amplifier circuits 75,77, 79 and 81, and an adder 83. Inputs of those PWM circuits 67, 69, 71and 73 are connected with the output terminal 65 of the light sourcedrive controller unit 13 (shown in FIG. 1, FIG. 3, FIG. 4 and FIG. 6),respectively. Thus, any one of the four (4) sets of PWM circuits 67, 69,71 and 73 is connected with the output terminal 65 of the light sourcedrive controller unit 13, in parallel with one another. The pulseamplifier circuit 75 is connected with an output of the PWM circuit 67,the pulse amplifier circuit 77 with an output of the PWM circuit 69, thepulse amplifier circuit 79 is connected with an output of the PWMcircuit 71, and the pulse amplifier circuit 81 with an output of the PWMcircuit 73, respectively. An input of the adder 83 is connected withoutputs of the pulse amplifier circuits 75, 77, 79 and 81.

The PWM circuits 67, 69, 71 and 73 input two (2) bits of the signal PLAMP of eight (8) bits, by each, which is inputted from the light sourcedrive controller unit 13 through the output terminal 65, and treat pulsewidth modulation on the above-mentioned two (2) bits signal inputted,upon basis of the bright/dark information for each pixel of the originalvideo data, which is indicated by each of the two (2) bits signalinputted. (Thus, an adjustments is made upon ON-time widths of theinputted signal LD AMP (i.e., the pulse signal), indicating thetime-period of displaying one (1) pixel within the video data to bedisplayed on the display area 31 (i.e., the time widths of lightemissions of the light sources (9, 57 and 61)).) With this, on thedisplay area 31 mentioned previously, a projection image of the originalvideo data is displayed, the brightness of which is ranked within theregion of 256 gradations for each pixel.

The pulse amplifier circuits 75, 77, 79 and 81 input the two (2) bitssignals (i.e., the pulse signals), after being adjusted upon the ON-timewidth thereof, which are outputted from the corresponding PWM circuits67, 69, 71 and 73, respectively, and amplify waveforms of the ON-timewidth of those two (2) bits signals (i.e., the pulse signals). And, theyoutput the signals after that (pulse) amplification, to the adder 83,respectively.

The adder 83 adds the (pulse) signals after being treated with the pulseamplification, which are outputted from the pulse amplifier circuits 75,77, 79 and 81, respectively. With this, a light source driver signals isproduced, which indicates a specific one gradation within the 256gradations, for a certain pixel within the original video data. Theadder 83 outputs that light source driver signal to the light sources(9, 57 and 61).

As was explained in the above, according to the fifth embodiment of thepresent invention, even if increasing the output energy from the lightsource (i.e., the light emission amount from the light source), forachieving the high brightness of the projection image, it is possible tobring the irradiation timings of the laser lights from the light sources(9, 57 and 59), for displaying the projection image on the display area31, to be synchronized with the oscillations of the micro mirror 1 inthe horizontal (H) direction and the vertical (V) direction, by means ofthe mirror driving/holding mechanism 3, at high accuracy, and therebyenabling prevention of ill effects from generating within the structuresof the micro mirror 1, also prevention of ill influences from beingexerted upon the driving (or oscillating) condition of the micro mirror1, and further enabling the video or image display with stability.

Also, upon basis of the electric signal PD1 outputted from thephoto/eclectic converter elements 43, intermittently, the position onthe display area 31 is determined, corresponding to the time-period fromstarting display of the projection image until finishing the displaythereof on the display area 31, every time when the micro mirror 1oscillates in the horizontal (H) direction and the vertical (V)direction, and with this, the display position of the projection imagecan be fixed on the display area 31, even under the condition where theoscillation of the micro mirror 1 changes in width thereof, andtherefore it is possible to reproduce the original video data under astable condition.

Also, when displaying the original video data on the display area 31,under the condition of oscillating the micro mirror 1 in the horizontal(H) direction and the vertical (V) direction, it is possible to adjustthe intensity of the laser lights to be irradiated from the lightsources (9, 57 and 61), in a step-like manner, thereby enabling toachieve bright/dark gradation display with high accuracy. Also, addingthe signals, which are outputted from the plural number of pulseamplifier circuits (75, 77, 79 and 81), respectively, within the adder83, enables to increase the number of gradations, with ease, for thepurpose of enabling to express the degree of brightness/darkness foreach of pixels building up the original video data, finely, withoutincreasing processing speed within the circuit operations. Further, bydetermining an overlap of the laser beam light between the pixelsthemselves, neighboring to each other in the oscillation direction ofthe micro mirror 1, for each of the gradations, it is also possible toconduct a control on definitions (i.e., an extension of a pixel) foreach of the pixels, with ease.

While we have shown and described several embodiments in accordance withour invention, it should be understood that disclosed embodiments aresusceptible of changes and modifications without departing from thescope of the invention. Therefore, we do not intend to be bound by thedetails shown and described herein but intend to cover all such changesand modifications that fall within the ambit of the appended claims.

1. An image displaying apparatus, comprising: a reflection mirror, whichis configured to display an image on a projection object, upon receivinga light irradiated from a light source thereon, to reflect it into apredetermined direction; a reflection mirror vibrating mechanism, whichis configured to vibrate said reflection mirror into a predetermineddirection; a temperature presuming unit, which is configured to presumetemperature on said reflection mirror, depending on driving condition ofsaid light source; and a vibration condition adjusting unit, which isconfigured to adjust condition of the vibration of said reflectionmirror by said reflection mirror vibrating mechanism, to becorresponding to the temperature on said reflection mirror, which ispresumed within said temperature presuming unit.
 2. The image displayingapparatus, as is described in the claim 1, wherein said reflectionmirror vibrating mechanism comprises: a first vibration mechanism, whichis configured to vibrate said reflection mirror in a first axialdirection; and a second vibration mechanism, which is configured tovibrate said reflection mirror in a second axial direction,perpendicular to said first axial direction.
 3. The image displayingapparatus, as is described in the claim 1, wherein said temperaturepresuming unit presumes the temperature on said reflection mirror, uponbasis of accumulated value data of a light amount irradiated from saidlight source, per every predetermined time-period.
 4. The imagedisplaying apparatus, as is described in the claim 3, wherein saidvibration condition adjusting unit adjusts vibration amplitude,vibration frequency, or vibration phase of said reflection mirror bysaid reflection mirror vibrating mechanism, to be corresponding to thetemperature on said reflection mirror, which is presumed within saidtemperature presuming unit.
 5. The image displaying apparatus, as isdescribed in the claim 4, wherein the adjustment upon the vibrationcondition of said reflection mirror, which is conducted by saidvibration condition adjusting unit, is conducted such that a locus ofthe light reflected through said reflection mirror on said projectionobject is in conformity with an ideal condition of the locus of saidlight on said projection object.
 6. An image displaying apparatus,comprising: a reflection mirror, which is configured to display an imageon a projection object, upon receiving a light irradiated from a lightsource thereon, to reflect it into a predetermined direction; areflection mirror vibrating mechanism, which is configured to vibratesaid reflection mirror into a predetermined direction; a photo detectorunit, which is configured to output a predetermined electric signal,after detecting a light incident upon said projection object throughsaid reflection mirror; a vibration condition detector unit, which isconfigured to detect a vibration condition of said reflection mirror,upon basis of the electric signal outputted from said photo detectorunit; and a controller unit, which is configured to control saidreflection mirror vibrating mechanism, so as to bring the vibrationcondition of said reflection mirror into a desired vibration condition,upon basis of the vibration condition of said reflection mirror, whichis detected by said vibration condition detector unit.
 7. The imagedisplaying apparatus, as described in the claim 6, wherein saidvibration condition detect or unit detects vibration amplitude,vibration frequency, or vibration phase of said reflection mirror, whichare obtained by measuring a distance between the electric signalsoutputted from said photo detector unit.
 8. The image displayingapparatus, as described in the claim 6, wherein said photo detector unitcomprises: a photo transmitting member, which is disposed in saidprojection object and is configured to transmit a light incidentthereupon; and a photo/electric converter element, which is configuredto input the light transmitted through said photo transmitting member,so as to output a predetermined electric signal therefrom.
 9. The imagedisplaying apparatus, as described in the claim 6, wherein said photodetector units are disposed within said projection object, in pluralnumber of sets thereof.
 10. The image displaying apparatus, as describedin the claim 9, wherein said light source includes therein: a red colorlight source for irradiating a red color light towards said reflectionmirror; a green color light source for irradiating a green color lighttowards said reflection mirror; and a blue color light source forirradiating a blue color light towards said reflection mirror.
 11. Amethod for adjusting vibration condition of a reflection mirror, withinan image displaying apparatus, having: a reflection mirror, which isconfigured to display an image on a projection object, upon receiving alight irradiated from a light source thereon, to reflect it into apredetermined direction; and a reflection mirror vibrating mechanism,which is configured to vibrate said reflection mirror into apredetermined direction, comprising the following steps of: a first stepfor presuming temperature on said reflection mirror, responding ondriving condition of said light source; and a second step for adjustingvibration condition of said reflection mirror by said reflectionvibration mechanism, so as to fit the temperature on said reflectionmirror, which is presumed in said first step.